1. Field of the Invention
The present invention relates to an image acquisition apparatus.
2. Description of the Related Art
In image acquisition apparatuses such as a digital video camera or a digital still camera, there has been widely utilized a zoom function which changes a focal distance of a lens in accordance with a distance to a subject to be shot or a size occupied in a field angle and performs zooming without restraint. Usually, the zoom function is roughly classified into optical zooming which is realized by mechanically moving a lens and electronic zooming which utilizes a part of an image output from an imaging element and interpolating new pixels between pixels to perform zooming in and thins out pixels to effect zooming out. Although electronic zooming can be inexpensively realized with a small size since it does not require a driving portion, it is inferior in an image quality as compared with optical zooming.
On the other hand, in Jpn. Pat. Appln. KOKAI Publication No. 1998-233950, a fixed focal distance image input optical system having a function of compressing a peripheral region of an input image and a light receiving element which receives an incident subject image through the fixed focal distance image input optical system and mainly has a uniform pixel density are provided, and an image including a distortion due to compression in the fixed focal distance image input optical system is subjected to correcting conversion, thereby realizing a zoomed image having a resolution equivalent to that of optical zooming in an operating region. According to the technique described in Jpn. Pat. Appln. KOKAI Publication No. 1998-233950, deterioration in image quality in a peripheral region of both a wide-angle image and a telephoto image is unavoidable, but acquisition of an image which is less deteriorated in a central region thereof can be expected.